Well, searching the ‘net for any decent info on Google Analytics Cookies is not easy! I want to start writing my own javascript hacks so I am currently looking for some excellent resources to help me build my knowledge. If you know any — please don’t keep them to yourself!

Any hoo… I think I have found one – Extracting useful data from your Analytics cookies . In particular, the site references the cookie, __utmz which stores data about how a visitor arrived at your site and how you can extract data to use in your analytics tracking.